Bug 1009817 (CVE-2013-4361)

Summary:	CVE-2013-4361 Kernel: Xen: Xsa-66: information leak through fbld instruction emulation
Product:	[Other] Security Response	Reporter:	Prasad Pandit <ppandit>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	drjones, imammedo, mrezanin, pbonzini, rkrcmar, security-response-team
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2013-09-30 17:10:26 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1013748
Bug Blocks:	1009366

Description Prasad Pandit 2013-09-19 08:31:26 UTC

The emulation of the fbld instruction (which is used during I/O
emulation) uses the wrong variable for the source effective address.
As a result, the actual address used is an uninitialised bit pattern
from the stack.

A malicious guest might be able to find out information about the
contents of the hypervisor stack, by observing which values are
actually being used by fbld and inferring what the address must have
been. Depending on the actual values on the stack this attack might
be very difficult to carry out.

A malicious guest could use this flaw to access memory bytes related to other
guests.

Comment 1 Prasad Pandit 2013-09-19 08:38:19 UTC

Statement:

This issue does not affect the versions of the kernel-xen package as shipped with Red Hat Enterprise Linux 5.

This issue does not affect the versions of the Linux kernel package as shipped with Red Hat Enterprise Linux 6 and Red Hat Enterprise MRG as it does not have support for Xen hypervisor.

Comment 2 Prasad Pandit 2013-09-19 08:40:23 UTC

Acknowledgement:

Red Hat would like to thank the Xen project for reporting this issue.

Comment 5 Vincent Danen 2013-09-30 17:10:26 UTC

This is now public:

http://www.openwall.com/lists/oss-security/2013/09/30/3

Comment 6 Vincent Danen 2013-09-30 17:14:29 UTC

Created xen tracking bugs for this issue:

Affects: fedora-all [bug 1013748]